This invention relates to an apparatus for phasing and transferring rod-shaped articles between conveying drums which are rotating at different peripheral speeds, and, more particularly, a device for phasing and transferring cigarettes between two vacuum drums having different peripheral rotational speeds.
Traditionally, in the tobacco industry, during the manufacture of cigarettes, the cigarettes are conveyed on the machinery from one point to another by rotating drums which have a plurality of recessed seats or pockets on their peripheral surface. A vacuum or negative pressure system is used to hold the cigarettes on the seats as the drums rotate. Each cigarette is retained in a fixed position on the drum by using the vacuum; and, upon transfer, the vacuum on the carrying drum is terminated and the vacuum on the pick-up drum is initiated.
In many instances, the drums are of different diameters; and, although the angular speed of the drums may differ, the peripheral speed of the surface of the drum must be the same and each drum must be phased relative to the other drums in order for the cigarettes to be transferred between the drums. This phasing can be done relatively easy if all drums are driven by the same source.
A problem occurs, however, when the drums are being driven from two different sources. Phasing the drums becomes very difficult and mechanically keeping the drums in synchronization is almost impossible.
In most instances, it is possible to drive all of the conveying drums from the same source; however, there are situations when two driving sources are advantageous--for example, where it is desirable not to interrupt the final processing operation should the initial processing operation cease to function. One such situation is illustrated in my co-pending U.S. patent application Ser. No. 859,615 filed Dec. 12, 1977 and entitled METHOD AND APPARATUS FOR PERFORATING AN ASSEMBLED FILTER USED ON A SMOKING PRODUCT.
The forming drum illustrated in this co-pending application usually requires heat to form the holes in the cigarette filters. If the forming drum were connected directly to the filter cigarette assembler drive mechanism and a problem were encountered in the assembly phase of the operation producing or requiring a stoppage, the forming drum would also stop. If such a stoppage occurs, the forming drum would contain cigarettes at various stages of formation. Some of the filters would have heated piercing members inserted therein. As is set forth in my earlier application, the time period for applying the heated piercing members to the filters has to be precisely controlled, otherwise, the holes will not be uniform in shape to produce the proper air dilution flow through the filter.
To insure that the heat is applied for the proper period of time, it is essential to remove the cigarettes in the forming drum should a stoppage in the initial operation stage of the assembler occur. The most logical way to accomplish this objective is to have a separate drive source for the forming drum which would cause the forming drum to continue to operate even when the assembler stops. Since it is almost impossible to mechanically maintain two driving sources in phase, there exists a need for a phasing and transferring apparatus which will allow the transferring of cigarettes between conveying drums operating at different peripheral speeds produced by using separate driving sources.